Translating dwell cleaning system

ABSTRACT

In an electrostatographic imaging surface blade cleaning system in which a cleaning blade is cyclically translated laterally of the normal direction of motion of the imaging surface between two substantially spaced apart translation end dwell positions, an irregular multi-lobe can blade drive is provided for the cyclic lateral translation of the cleaning blade and also for automatically multiply slightly shifting the blade end dwell positions on the imaging surface without requiring a major decrease in their maximum available spacing.

United States Patent 1191 Jones l Dec. 17, 1974 [54] TRANSLATING DWELL CLEANING 1,372,408 3/1921 Dyson ..L.., 74/569 SYSTEM 1 1,922,959 8/1933 Kerst et a1. 3,724,020 4 1973 Till l5/256.53

Filed:

Robert N. Jones, Fairport, NY.

Xerox Corporation, Stamford,

Inventor:

Assignee:

Conn.

Aug. 24, 1973 Appl. No.: 391,195

u.s. c1 ass/1s, 15/256.53, 74/569, 100/174, 101/425 Int. Cl G03g 15/00 3 Field of Search 15/256.53, 256.51, 256.5;

References Cited UNITED STATES PATENTS Adams 74/569 Primary Examiner-Edward L. Roberts [57] ABSTRACT In an electrostatographic imaging surface blade clean- I ing system in which a cleaning blade is cyclically translated laterally of the normal direction of motion 'of the imaging surface between two substantially 'quiring a major decrease in their maximum available spacing.

2 Claims, 3 Drawing Figures hereby incorporated fication,-

The present specification-embodiment discloses a,

' translation TRANSLATING DWELL CLEANING. SYSTEM The present invention relates to electrostatographic imaging surfaceblade cleaningsystems, and in particular to such a systemproviding changes in theenddwell positions of a translating cleaningblade.

A problem in the use of cleaning'blade systems for cleaning moving xerographic. photoreceptor imaging surfaces of imaging material has. been'the tendency of blade edgev sealing failures, such aslocalized tuck 'unders, to occur at points where the blade edgeis being eral translation during machine operationis' used, there will be two fixed position end-dwell positions on the photoreceptorat which the blade stops at the same place to reverse in each translation cycle. Thus, in

these two dwell points-the, blade is hot fully protected bytranslation from the above-described. single point multiple impacts from the same defectson the photore ceptor. Another'approach to blade translation is disclosed in U.S; Pat-No. 3,740,789 and the 3100 machine cited below. This involves moving the blade in a I series of short separate steps in each direction of major translation. However, this results in a large number of dwell points for each full blade translation cycle. The present invention provides a-solution to the above described problem by a simple. means for cyclically shifting the twoend dwell points of a continuous blade translation system without substantially affecting the full available translation stroke length, thereby providing an increased effective lifetime for the blade. I

figuration and speed to provide the desired multiple shifting of the blade translation end dwell, positions.- This'modification may also, however, eliminate the need: for the additional-structure for continuing the blade translation after: machine stoppage taught by these same two patents. lnview of-theexisting teaching provided by these two-patents, there is no need in the. following specification description to discuss .the co m-, mon and-associatedffeatures andstructuresin any detail.

Further features and advantages of the presennt invention pertain to the particularapparatusand func-.

tions whereby the above-mentioned aspects of the invention are attained-Accordingly, theinvention will be better understood by'reference to the following description and to the drawings. forming a part thereof, which are substantially to sc ale,wherein:

- FIG. 1 isa planview of an exemplary embodiment' of the present cleaning blade system; 1

I FIG. Zis an enlarged detail; of thedrive cam and cam follower from FIG. 1 and 1 FIG. 3 is an alternativeembodiment of the drive cam and cam follower of F-lGS. 1 and 2;.

' Referring now to the drawings,- FIGS! 1 through 3,

and first of theembodiment'of FIGS. 1 and 2, there is shown therein an examplary blade cleaning system 10 in accordance with the present invention for cleaningtoner from thephotoreceptive imaging surface llof a xerographic drum 142 The surface 12 is cleaned by a contacting cleaning blade 16, extending transverse the direction of movement (rotation) of the imaging surface 12. The 'presen't inventionrelates particularly to a blade drive system 20 for laterally oscillating the clean- -ing blade 16 back and forth across the-imaging surface 12, as illustrated by the arrow in-FIG. l.

' The bladedrive system 20 provides improved cleaning blade life and reliability by, in addition to translating the cleaning blade, also shifting or translatingv the Exemplary xerographic photoreceptor blade type dry toner cleaningapparatus, to which the present invention relates,-is disclosed in'U.S. Pat. Nos. 3,438,706'is sued Apr. 15, 1969, to -H.'Tanaka et al.; 3,552,850 issued Jan. 5, 1971, to SF. Royka etaL; 3,634,077 issued Jan. 1 l, l972,to W. A. Sullivan;3,660,863 issued May 9, 1972 to D. P. Gerbasi; 3,724,019 issued Apr. 3,

1973 to Alan L. Shanlyj 3,724,020 issued Apr. 3,1973

to Henry R. Till; and 3,740,789 issuedJur'ie 26, 1973 to Raymond G. Ticknor.'Pending applicationszincludc U.S. Applications Ser. No. 356,985, filed May 3, 1973, by Richard E. Smith (D/7300zl) andSer. No. 356,986, filed May 3,1973, by Christ S .ll-lasiotis' (D/73l96). Toner cleaning'systems witha-translatingpolyurethane cleaning blade are commercially embodiedv in the Xerox Corporation 4000 and 3100""xerographic copiers. The present invention; islan improvement in this technology, and accordinglythese references are by reference in;thepresentspecispecific improvement inthe xerographi'c cleaning'blade structure disclosed in the aboveincorporated UQSQ -Pat. Nos. 3,724,019 and 3,724,020 and the Xerox 4000 copier, requiring only a'modifirotational speed; Asin these tworeference patents,.the I camZjZ is. driven about a-fixedaxis of rotation 24at a' relatively slow speed by a conventional small electric motor. 26 and conventional integral gear reduction two end dwell positions in which the cleaning blade 16 stops at the end ofeach lateral extreme of theblade os cillation. These two dwell points have been foundto be the initial failure points of the blade when only simple blade translation is provided. The blade drivesystem. '20, utilizing'a multilobe cam drive, shifts or moves these end dwell positions by a small distance in each cycle to substantially increase the number of dwell positions and thereby assist in "extendingthe effective. cleaning blade life.

The cleaning system 10 here is thesame as that disclosed in the two' above-referenced US. Pat. Nos. 3,724,019 and 3,724,020, except forthe provision. of a multi-lobe-cam 2 2and the preferred use of a lower cam unit. Howeventhe cam of thesetwo reference-patents is aheart-shaped single=lobecam, whereas the cam'22 .js multi-lobed. As far as'the cam 22rot'ational speed, if thesame approximate blade translationalspeeds are to be utilized. as in; the systemdescribedin; these;- two patents, the. gear reduction-from themotor 26shouldbe cation thereof comprising changing the drive cam conincreased approximately in proportionto theincrease inthe number of cam'lobes,

Similarly to the'two above-referenced.patents,the

rotation of the cam 22 causes the lobesofi the cam;2-2

topush upwardly on one armof an engaging camt follower 28, whichthereby oscillates about its own pivotal axis 30. An equal length'arm of the cam follower 28 on the opposite side of the axis 30 from the cam engaging arm is pivotally secured to, and linearly moves, a pull rod 32. The pull rod 32 in turn is directly connected for translation to the cleaning blade 16. The pull rod 32 thereby pulls the cleaning blade 16 toward the drive system 20 during the rise or lift portion of the cam surface movement toward the cam lobe apex. The return motion of the cleaning blade is provided by a coil spring 34 under tension pulling on the opposite side of the cleaning blade 16 mounting, in opposition to the pull rod 32.

The above-described operation of the blade, drive system 20, and particularly the configuration of the multilobed cam 22, is best seen in FlG. 2. It may be seen that the particular exemplary cam 22 here has five flat faceted lobes, which are sharply peaked or pointed at their apexes for minimum blade dwell times at the lobe peaks. lt may be particularly seen that each of the cam lobes has a different maximum (apex) distance or radius of revolution from the axis 24 of rotation of the cam 22. These distances are shown, for example, for the highest cam lobe by the arrow A and for the lowest cam lobe by the arrow B. Theycorrespond directly to the positions of one of the two end dwell points. The minimum cam surface radius between each lobe corresponds to the other end dwell point, and it may be seen that these are all different also.

Each'lobe of the cam 22'provides a full oscillation of the cleaning blade 16 for substantially as great a distance as could be provided by a single lobe cam, and

i with no substantial increase in the dwell times. However, each lobe here has different maximum and minimum radii of revolution about the axis 24 and therefore provides slight shifting or cyclic changes of both of the two translation end dwell'positions of the blade. This shifting occurs automatically in response to, and as a part of, the blade oscillation, without any stopping of the blade motion between the two dwell positions. The cleaning blade 16 does not step transversely across the imaging surface 12 in small steps from oneside to another. Rather, it fully cyclically traverses to substantially the maximum practical and usable extent in each I cycle with eachicam'lobe. j

Although not essential, a desirable additional feature 3 provided by the drive system 20 is the irregular spacing in angular and circumferential distance of the cam lobes around the axis 24. This provides a cyclic changing of the blade translation speed and total translation time for each cam lobe, which is desirable. The more irregular the motion, the less likelyis that the blade or harmonically with t'ions of adjacent blade oscillations are the same. They are spaced apart in time -by four intervening oscillaof said cleaning blade and for automatically multiply two end'dwell positions of the blade. The stroke length can, of course, be changed as well, if desired, by appropriate design of the cam surface, but it is not necessary with the disclosed system vto sacrifice the utilization of a large percentage of the maximum stroke length between the most extreme allowable end dwell positionstturn for helping to break up excessive toner, lubricant,

or contaminant build-up on the cleaning blade edge. In other respects. the embodiment of FIG. 3 is similar in structure and operation to that of FIGS. 1 and 2 described above.

Merely as exemplary. of suitable blade translation speeds but not limited thereto,' a blade translation velocity of between approximately-0.5 l0 centimeters per second and 0.2 centimeters per second is appropriate for cleaning with distributed blade wear. Likewise, an amplitude of oscillation (distance between dwell points) of greater than approximately 0.15 centimeters but not extending off of the imaging surface is suitable.

Various other-modifications or improvements will be apparent to those skilledin theart, although the'exemplary embodiments described herein are presently considered to 'be preferred. The following claims are intended to cover all variations and modifications as fall within the'true spirit and scope of the invention.

What is claimed is: Y i i 1. An electrostatog raphic imaging surface blade cleaning system in which a cleaning blade is cyclically oscillated laterally of the normal direction of motion of the imaging surface: between two substantially spaced apart translation end dwell positions of said blade on said-imaging surface, wherein the improvement comprises a blade drive means for cyclic lateral oscillation slightly shifting the positions on said imaging surface of said two blade translation end dwell positions without stopping the blade motion between said two translation end dwell positions,

tions. Thus, it may be seen that the tendency for blade failures to occur in proportion to'the time spent in a given dwell position is substantially reduced. Yet, it will also be observed that this is accomplished here without necessarily substantially decreasing the overall blade stroke length, i.e.'the translation distance between the wherein said blade drivemeans comprises a multilobe cam rotatably driven about an axis of rotation and a-camfollower driven by said multi-lobe cam, said cam follower being drivingly connected to said' blade for cyclic translation of said blade-by .said

cam, and wherein said multi-lobe cam has a plurality. of cam lobes having different maximum and minimum radii of revolution about said axis for said automatic shifting of said two blade translation end dwell positions at each said cyclic translation of e of said blade translation. 

1. An electrostatographic imaging surface blade cleaning system in which a cleaning blade is cyclically oscillated laterally of the normal direction of motion of the imaging surface between two substantially spaced apart translation end dwell positions of said blade on said imaging surface, wherein the improvement comprises a blade drive means for cyclic lateral oscillation of said cleaning blade and for automatically multiply slightly shifting the positions on said imaging surface of said two blade translation end dwell positions without stopping the blade motion between said two translation end dwell positions, wherein said blade drive means comprises a multi-lobe cam rotatably driven about an axis of rotation and a cam follower driven by said multi-lobe cam, said cam follower being drivingly connected to said blade for cyclic translation of said blade by said cam, and wherein said multi-lobe cam has a plurality of cam lobes having different maximum and minimum radii of revolution about said axis for said automatic shifting of said two blade translation end dwell positions at each said cyclic translation of said blade by said cam.
 2. The system of claim 1, wherein said cam lobes are also irregularly spaced angularly around said axis with respect to one another to cyclically change the speed of said blade translation. 